A new two-parameter family of mean velocity profiles for incompressible turbulent boundary layers on smooth walls

Abstract

The combination of two universal functions, representing the effects of the wall and of the 'intermittency' in the other region, has been used to construct a new profile family. Comparisons with measured profiles are very satisfactory for a wide range of local and of upstream conditions, whilst the skin-friction values should be rather more reliable than those of the well known Ludwieg and Tillmann relationship. In severe adverse pressure gradients the 'universal' wall law breaks down and an estimate is given for the range of pressure gradient beyond which no two-parameter family is likely to be satisfactory.